Even limited arsenic exposure can mar cognitive ability: study

It caused a reduction in grey matter in the brain and affected concentration in children and young adults, say researchers who worked with 1,014 participants from five regions across India

Though it is well known that ingesting high levels of arsenic from contaminated groundwater in India has been linked to a range of ailments, a recent peer-reviewed study suggests that even low levels of arsenic consumption may impact cognitive function in children, adolescents, and young adults.

The research study, which is part of a bigger investigation into how a range of environmental and biological factors affect neurological and cognitive development in young people, also found that those exposed to arsenic had reduced grey matter (brain tissue that is vital to cognitive functions) and weaker connections within key regions of the brain that enable concentration, switching between tasks, and temporary storage of information.

“Chronic exposure to arsenic could be creating a ‘silent pandemic’ affecting large portions of the global population,” say the authors in the study published in the latest issue of the peer-reviewed journal, JAMA Network Open.

For their research, the scientists linked urine samples (to estimate arsenic exposure) performance in a battery of computerised tests (that evaluate cognitive function) and brain-images (that picturise various regions of the brain) of 1,014 participants from five regions across India.

Arsenic exposure, previous studies have shown, is particularly harmful to the poor.

However, a scientist associated with the study told The Hindu that the impact of arsenic in impairing cognition at an individual level was “limited”. The effect was more pronounced when individuals were considered as part of a collective, the scientist said.

Mapping brains

“We didn’t set out to investigate the link between arsenic exposure and brain function... it emerged from the C-Veda data. Going ahead, we’d like to more thoroughly investigate the degree to which arsenic affects the brain. We are also looking at the role of a host of other environmental factors, in separate studies, such as air pollution,” Nilakshi Vaidya, clinical psychologist and lead author of the study, told The Hindu in a phone conversation.

Since the 1990s, both the Central and State governments in Bihar and West Bengal have sought to address arsenic contamination. A common strategy employed is to encourage piped water access rather than groundwater extraction and install arsenic removal plants.